diff --git a/3d Prototyp/Assets/Scenes/GameLoopTest.unity b/3d Prototyp/Assets/Scenes/GameLoopTest.unity
index bacb6fb2..47241bd3 100644
--- a/3d Prototyp/Assets/Scenes/GameLoopTest.unity	
+++ b/3d Prototyp/Assets/Scenes/GameLoopTest.unity	
@@ -227,6 +227,7 @@ GameObject:
   m_Component:
   - component: {fileID: 283529458}
   - component: {fileID: 283529457}
+  - component: {fileID: 283529459}
   m_Layer: 0
   m_Name: Game Manager
   m_TagString: Untagged
@@ -243,13 +244,14 @@ MonoBehaviour:
   m_GameObject: {fileID: 283529456}
   m_Enabled: 1
   m_EditorHideFlags: 0
-  m_Script: {fileID: 11500000, guid: 54747ffb706c8df4bbb0c0ca3e60a560, type: 3}
+  m_Script: {fileID: 11500000, guid: 4c31bfd8f0f10f540b73de81aac6d46c, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
   _baseGameDurationSeconds: 600
-  _currentEfficiency: 0
   _remainingGameDurationSeconds: 0
-  _developers: []
+  _currentEfficiency: 0
+  _developers:
+  - {fileID: 283529459}
 --- !u!4 &283529458
 Transform:
   m_ObjectHideFlags: 0
@@ -265,6 +267,18 @@ Transform:
   m_Children: []
   m_Father: {fileID: 0}
   m_LocalEulerAnglesHint: {x: 0, y: 0, z: 0}
+--- !u!114 &283529459
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 283529456}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: 6dcc72027d5c35441a351fdb5140b0f8, type: 3}
+  m_Name: 
+  m_EditorClassIdentifier: 
 --- !u!1 &1737307722
 GameObject:
   m_ObjectHideFlags: 0
diff --git a/3d Prototyp/Assets/Scripts/Developer.cs b/3d Prototyp/Assets/Scripts/Developer.cs
index b3feff53..5844c954 100644
--- a/3d Prototyp/Assets/Scripts/Developer.cs	
+++ b/3d Prototyp/Assets/Scripts/Developer.cs	
@@ -8,4 +8,9 @@ public class Developer : MonoBehaviour
     /// Gibt die Effizienz des Entwicklers in Prozent zurück.
     /// </summary>
     public float Efficiency => 1.0f;
+
+    public void UpdateEfficiency()
+    {
+        // TODO: Implement 
+    }
 }
diff --git a/3d Prototyp/Assets/Scripts/GameManager.cs b/3d Prototyp/Assets/Scripts/GameManager.cs
index 9d2a07c1..5eec86e3 100644
--- a/3d Prototyp/Assets/Scripts/GameManager.cs	
+++ b/3d Prototyp/Assets/Scripts/GameManager.cs	
@@ -9,24 +9,21 @@ public class GameManager : MonoBehaviour
     public static GameManager Instance { get; private set; }
 
     [SerializeField]
-    private double _gameProgress = 0.0;
+    private double _baseGameDurationSeconds = 10.0 * 60.0;
 
     [SerializeField]
-    private double _baseGameDurationSeconds = 10.0 * 60.0;
+    private double _remainingGameDurationSeconds = 0.0;
 
     [SerializeField, ShowOnly]
     private double _currentEfficiency = 0.0;
     
-    [SerializeField, ShowOnly]
-    private double _remainingGameDurationSeconds = 0.0;
-    
     [SerializeField]
     private List<Developer> _developers = new();
     
     /// <summary>
-    /// Wie weit das Spiel bereits fortgeschritten ist.
+    /// Wie weit das Spiel bereits fortgeschritten ist, in Prozent.
     /// </summary>
-    public double GameProgress => _gameProgress;
+    public double GameProgress => 1.0 - (_remainingGameDurationSeconds / _baseGameDurationSeconds);
     
     /// <summary>
     /// Wie Effizient das Team derzeit arbeitet.
@@ -36,17 +33,7 @@ public class GameManager : MonoBehaviour
     /// <summary>
     /// Wie viele Sekunden das Spiel voraussichtlich noch dauern wird, würden die Effizienz sich nicht verändern.
     /// </summary>
-    public double RemainingGameDurationSeconds => _remainingGameDurationSeconds;
-    
-    /// <summary>
-    /// Wie lange das Spiel voraussichtlich noch dauern wird, würden die Effizienz sich nicht verändern.
-    /// </summary>
-    public TimeSpan RemainingGameDuration => TimeSpan.FromSeconds(_remainingGameDurationSeconds);
-    
-    /// <summary>
-    /// Wie lange voraussichtlich das gesamte Spiel dauern wird.
-    /// </summary>
-    public double ExpectedTotalGameSeconds => 0.0;
+    public double ExpectedRemainingGameDuration => _remainingGameDurationSeconds / _currentEfficiency;
     
     private void Awake()
     {
@@ -59,9 +46,16 @@ public class GameManager : MonoBehaviour
             Debug.LogError("GameManager already exists. Deleting duplicate.");
             Destroy(gameObject);
         }
+        
+        InvokeRepeating(nameof(UpdateProgress), 0.0f, 1.0f);
     }
 
-    void Update()
+    private void Start()
+    {
+        _remainingGameDurationSeconds = _baseGameDurationSeconds;
+    }
+
+    void UpdateProgress()
     {
         UpdateEfficiency();
         UpdateGameDuration();
@@ -69,13 +63,20 @@ public class GameManager : MonoBehaviour
 
     void UpdateEfficiency()
     {
-        _currentEfficiency = _developers.Sum(d => d.Efficiency);
+        double developerEfficiency = 0.0f;
+        
+        foreach (Developer developer in _developers)
+        {
+            developer.UpdateEfficiency();
+            developerEfficiency += developer.Efficiency;
+        }
+        
+        _currentEfficiency = developerEfficiency;
     }
 
     void UpdateGameDuration()
     {
-        double baseSecondsLeft = _baseGameDurationSeconds * (1.0 - GameProgress);
-
-        _remainingGameDurationSeconds = baseSecondsLeft / _currentEfficiency;
+        // Entwickler Effizienz ist im Grunde wie viele Entwicklersekunden wir pro Sekunde verrichten können.
+        _remainingGameDurationSeconds -= _currentEfficiency;
     }
 }